加载bmp文件方法一

第一步：定义类CMyTexture

MyTexture.h文件内容：

typedef struct _ImageRec {    unsigned short imagic;    unsigned short type;    unsigned short dim;    unsigned short xsize, ysize, zsize;    unsigned int min, max;    unsigned int wasteBytes;    char name[80];    unsigned long colorMap;    FILE *file;    unsigned char *tmp, *tmpR, *tmpG, *tmpB;    unsigned long rleEnd;    unsigned int *rowStart;    int *rowSize;} ImageRec;class CMyTexture  {public:CMyTexture();virtual ~CMyTexture();void bwtorgba(unsigned char *b,unsigned char *l,int n);void latorgba(unsigned char *b, unsigned char *a,unsigned char *l,int n);void rgbtorgba(unsigned char *r,unsigned char *g,unsigned char *b,unsigned char *l,int n); void rgbatorgba(unsigned char *r,unsigned char *g,unsigned char *b,unsigned char *a,unsigned char *l,int n); void ConvertShort(unsigned short *array, long length); void ConvertLong(unsigned *array, long length); ImageRec * ImageOpen(const char *fileName);void ImageClose(ImageRec *image); void ImageGetRow(ImageRec *image, unsigned char *buf, int y, int z); unsigned * read_texture(char *name, int *width, int *height, int *components); };

MyTexture.cpp内容：

CMyTexture::CMyTexture(){}CMyTexture::~CMyTexture(){}void CMyTexture::bwtorgba(unsigned char *b,unsigned char *l,int n){    while(n--){l[0] = *b;l[1] = *b;l[2] = *b;l[3] = 0xff;l += 4; b++;    }}void CMyTexture::latorgba(unsigned char *b, unsigned char *a,unsigned char *l,int n) {    while(n--) {l[0] = *b;l[1] = *b;l[2] = *b;l[3] = *a;l += 4; b++; a++;    }}void CMyTexture::rgbtorgba(unsigned char *r,unsigned char *g,unsigned char *b,unsigned char *l,int n) {    while(n--) {l[0] = r[0];l[1] = g[0];l[2] = b[0];l[3] = 0xff;l += 4; r++; g++; b++;    }}void CMyTexture::rgbatorgba(unsigned char *r,unsigned char *g,unsigned char *b,unsigned char *a,unsigned char *l,int n) {    while(n--) {l[0] = r[0];l[1] = g[0];l[2] = b[0];l[3] = a[0];        l += 4; r++; g++; b++; a++;    }}void CMyTexture::ConvertShort(unsigned short *array, long length) {    unsigned b1, b2;    unsigned char *ptr;    ptr = (unsigned char *)array;    while (length--) {b1 = *ptr++;b2 = *ptr++;*array++ = (b1 << 8) | (b2);    }}void CMyTexture::ConvertLong(unsigned *array, long length) {    unsigned b1, b2, b3, b4;    unsigned char *ptr;    ptr = (unsigned char *)array;    while (length--) {b1 = *ptr++;b2 = *ptr++;b3 = *ptr++;b4 = *ptr++;*array++ = (b1 << 24) | (b2 << 16) | (b3 << 8) | (b4);    }}ImageRec * CMyTexture::ImageOpen(const char *fileName){    union {int testWord;char testByte[4];    } endianTest;    ImageRec *image;    int swapFlag;    int x;    endianTest.testWord = 1;    if (endianTest.testByte[0] == 1) {swapFlag = 1;    } else {swapFlag = 0;    }    image = (ImageRec *)malloc(sizeof(ImageRec));    if (image == NULL) {fprintf(stderr, "Out of memory!\n");exit(1);    }    if ((image->file = fopen(fileName, "rb")) == NULL) {perror(fileName);exit(1);    }    fread(image, 1, 12, image->file);    if (swapFlag) {ConvertShort(&image->imagic, 6);    }    image->tmp = (unsigned char *)malloc(image->xsize*256);    image->tmpR = (unsigned char *)malloc(image->xsize*256);    image->tmpG = (unsigned char *)malloc(image->xsize*256);    image->tmpB = (unsigned char *)malloc(image->xsize*256);    if (image->tmp == NULL || image->tmpR == NULL || image->tmpG == NULL ||image->tmpB == NULL) {fprintf(stderr, "Out of memory!\n");exit(1);    }    if ((image->type & 0xFF00) == 0x0100) {x = image->ysize * image->zsize * sizeof(unsigned);image->rowStart = (unsigned *)malloc(x);image->rowSize = (int *)malloc(x);if (image->rowStart == NULL || image->rowSize == NULL) {    fprintf(stderr, "Out of memory!\n");    exit(1);}image->rleEnd = 512 + (2 * x);fseek(image->file, 512, SEEK_SET);fread(image->rowStart, 1, x, image->file);fread(image->rowSize, 1, x, image->file);if (swapFlag) {    ConvertLong(image->rowStart, x/(int)sizeof(unsigned));    ConvertLong((unsigned *)image->rowSize, x/(int)sizeof(int));}    } else {image->rowStart = NULL;image->rowSize = NULL;    }    return image;}void CMyTexture::ImageClose(ImageRec *image) {    fclose(image->file);    free(image->tmp);    free(image->tmpR);    free(image->tmpG);    free(image->tmpB);    free(image->rowSize);    free(image->rowStart);    free(image);}void CMyTexture::ImageGetRow(ImageRec *image, unsigned char *buf, int y, int z) {    unsigned char *iPtr, *oPtr, pixel;    int count;    if ((image->type & 0xFF00) == 0x0100) {fseek(image->file, (long)image->rowStart[y+z*image->ysize], SEEK_SET);fread(image->tmp, 1, (unsigned int)image->rowSize[y+z*image->ysize],      image->file);iPtr = image->tmp;oPtr = buf;for (;;) {    pixel = *iPtr++;    count = (int)(pixel & 0x7F);    if (!count) {return;    }    if (pixel & 0x80) {while (count--) {    *oPtr++ = *iPtr++;}    } else {pixel = *iPtr++;while (count--) {    *oPtr++ = pixel;}    }}    } else {fseek(image->file, 512+(y*image->xsize)+(z*image->xsize*image->ysize),      SEEK_SET);fread(buf, 1, image->xsize, image->file);    }}unsigned * CMyTexture::read_texture(char *name, int *width, int *height, int *components) {    unsigned *base, *lptr;    unsigned char *rbuf, *gbuf, *bbuf, *abuf;    ImageRec *image;    int y;    image = ImageOpen(name);        if(!image)return NULL;    (*width)=image->xsize;    (*height)=image->ysize;    (*components)=image->zsize;    base = (unsigned *)malloc(image->xsize*image->ysize*sizeof(unsigned));    rbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));    gbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));    bbuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));    abuf = (unsigned char *)malloc(image->xsize*sizeof(unsigned char));    if(!base || !rbuf || !gbuf || !bbuf)      return NULL;    lptr = base;    for(y=0; y<image->ysize; y++) {if(image->zsize>=4) {    ImageGetRow(image,rbuf,y,0);    ImageGetRow(image,gbuf,y,1);    ImageGetRow(image,bbuf,y,2);    ImageGetRow(image,abuf,y,3);    rgbatorgba(rbuf,gbuf,bbuf,abuf,(unsigned char *)lptr,image->xsize);    lptr += image->xsize;} else if(image->zsize==3) {    ImageGetRow(image,rbuf,y,0);    ImageGetRow(image,gbuf,y,1);    ImageGetRow(image,bbuf,y,2);    rgbtorgba(rbuf,gbuf,bbuf,(unsigned char *)lptr,image->xsize);    lptr += image->xsize;} else if(image->zsize==2) {    ImageGetRow(image,rbuf,y,0);    ImageGetRow(image,abuf,y,1);    latorgba(rbuf,abuf,(unsigned char *)lptr,image->xsize);    lptr += image->xsize;} else {    ImageGetRow(image,rbuf,y,0);    bwtorgba(rbuf,(unsigned char *)lptr,image->xsize);    lptr += image->xsize;}    }    ImageClose(image);    free(rbuf);    free(gbuf);    free(bbuf);    free(abuf);    return (unsigned *) base;}

第二：使用：

定义函数LoadTexture(char *fn, int t_num)，内容如下：

int texwid, texht;int texcomps; teximage = m_Tex->read_texture(fn, &texwid, &texht, &texcomps);if (!teximage){MessageBox("没有找到图形文件tr.rgb","错误",MB_ICONQUESTION);exit(0);}glBindTexture(GL_TEXTURE_2D, texture[t_num]);glPixelStorei(GL_UNPACK_ALIGNMENT, 1);glTexImage2D(GL_TEXTURE_2D, 0, 3, texwid, texht, 0, GL_RGBA, GL_UNSIGNED_BYTE, teximage);gluBuild2DMipmaps(GL_TEXTURE_2D, 3, texwid, texht, GL_RGBA, GL_UNSIGNED_BYTE, teximage);glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR); free(teximage);

声明参数：

CMyTexture*  m_Tex;unsigned *teximage;GLuint texture[6];